CA1052100A - Manganese containing fuels - Google Patents

Abstract

IMPROVED MANGANESE CONTAINING FUELS
ABSTRACT OF THE DISCLOSURE
Gasoline compositions containing manganese additives are improved by the addition of either a citrate compound having at least one alkyl group or a tetravalent tin compound having at least one alkyl group, both of which compounds must be soluble in gasoline and are added to the gasoline composition to improve the performance of the engine.

Description

ACK~,ROUND OF THE INVENllON
It is well kno~:n that lead gA~oline addltlves have been under attack due to envlronmental rea~on~. As a result~
there has been A search for sultable octane lmpro~ers that do not emplo~ lead. ~arlous mangane~e compounds have been ~ound ~nd are known to improve the octane ratlng o~ gRsollne composltlons.
Di~co~ery o~ these new mang~ne~e addltlves hRs presented addltional problem~ ln that now c~mpatlble additlves ~ust be found whlch allevlate problem~ caused by the use o~
manganese.
~ One problem encountered wlth the use of mangane~
addltive3 ls spark plu~, gap brld~lng and the re3ultant mls~irlng and en~lne mal~unction. Another ~roblem arises ~rom the use ~asoline contalnlng both manganese and lead addltl~es.
Thls comblnatlon resultQ in deposlts on the exhaust valve that reduce c~mpression pre~sure and lead to engine mal~unctlon ~5 due to burned exhaust val~es.

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SUMMARY OF THE l:NVENTION
It has now been discovered that the e problems of the art can be solved by the addition of a citrate compound for spark plug misfiring or a tetravalent tin compound for undesirable valve deposits. More specifically, the invention is a gasoline composition for combustion in a gasoline internal .
combustion engine comprising gasoline, a gasoline soluble ; ~;
manganese compound as an additive and a small but effective amount of a citrate compound having at least one alkyl group or a tetravalent tin compound having at least one alkyl group, each of said compounds being soluble in gasoline and acting ;~
as a gasoline additive to improve the performance of the gasoline internal combustion engine.
Thus, in accordance with the present teachings, an improvement is pro~ided in a gasoline composition or combustion in a gasoline internal combustion engine which comprises gasoline and a gasoline soluble manganese compound as an additive. The improvement comprises the inclusion of a ` small but effective amount of a tetravalent tin compound which has at least one alkyl group. The compound is soluble in gasoline and acts as a gasoline additive to improve the performance of the gasoline internal combustion engine. The small but e~fective amount is in the range of about 10 to about 75 milligrams of tin per gallon calculated on the tin contained in the alkyl tin compound.
The base fuel employed in the invention is gasoline containing a suitable manganese additive. The gasoline composition~ employed in this fuel are well known in the art.
The manganese compounds although less well known are readily 30 available on a commercial basis. Suitable manganese compounds have been invented and publicized by various companies especially the Ethyl Corporation. One of the most prominant B ~ -2- '~`

s~ o of the manganese additiYes is methyl cyclopentadienyl manganese ::, tricarbonyl. Use of this additi~e in the ~ase fuel of the present invention is especially preferred.
The present invention is the incorporation of either an alkyl tin compound or an alkyl citrate compound into these manganese base fuels. The alkyl tin compound in our ex-periments showed the ability to substantially reduce the deposits in the valve closures and ~he alkyl.. citrate compounds ~`
substantially reduced the misfirings of the internal combustion engines.

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The alkyl citrate compound~ employed ln the present inventlon may vary wldely. Broadly these alkyl cltrate compounds are citrates that contaln at least one alkyl ~roup.
Preferred citrates are tho~e that contain three alXyl groups o~ about 2 to 4 carbon atom~. The alkyl citr~te must ~e soluble ln the mangane~e ga80llne composltion and it mu~t be present in the man~anese compo~it~on in a concentratlon that improves the per~ormQnce of the internal combustion englne. From our experlence, prlmarlly related to the use of triethyl cltr~te~ sult~blQ concentratlons range from about lO to about lôO milll~rRms o~ trlethyl citrate per ~allon, For other cltrates, the concentration could be determlned from these us~ges o~ trlethyl cltrate.
me tetravAlent tln compound havlne at least one a:Lkyl group may al~o vary widely, Thi8 addltive may be ~ `~
employed alone or in comblnation with the citxate addltive.
Preferred i8 the use o~ this addltlve in comblnatlon with the citrate addltlve. Also pre~erred are th~ tetra alkyl tin compounds~ especially those tetrA alkyl tin compounds that have ~lk~yl group~ o~ 3-6 carbon ~tom~ each, The alkyl - tln compound must ~lso be soluble ln the manganese con~ainlng .
composition and thl~ tin additive should be present in concentrations that ~ub~tantiall~ reduces the valve deposit~.
Suitable range~ o~ concentratlons ~or the tin addltlve range from about 10 to about 75 milli~rams o~ tin per ~allon calculated on the tin rather than the total weight o~ the alkyl tln compound~ m e~e concentratlons are based on our experlment~ wlth tetra but~l tin and can be adJu~ted ~pproprlately ror other tin compounds.

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(4779) ~5'~Q 0 In sdditlon to the addltlve~ specl~icQlly requlr~d by the present inv~ntion, the ~nsoline compo~ltions encompassed by the in~entlon would include other additl~es that are known and develop~d wh~ch ~ould not interfere wlth the ~unctions o~ .
the additives of the lnventlon. Thu~, ror example, in --addltlon to the manganese additlve and the tln compound or the cltrateg ~u~tsble lnhlbitors or other addltives could ~ .
be employed.

SPECI~IC EMBODIMENTS ;.
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A].l examples Or the pre~ent lnventlon were run usln~ ~ b~s~ ruel having an inltial octane ratin~ o~ about _ 93 R.O.N. To thls fuel WR5 added 0,~ grams per gall~n o~
mangunese as methyl cyclopentadlenyl manganese trlc~r~o~yl. -~
In 2dditlon~ the fual contain~d 340 p.p.m. Oronite oGA_472 and l/8 o~ one percent SEB_7 Thl~ fuel exhlbited a 96 R.O.N. ~o rQpresent a lead contamlnated ~uel, ~.5 gr~m~ ~ :
per gallon o~ lead9 ~,tetra ethyl lead~ wa~ Rdded to thl~
~angQnese ~uel.
All experi~nt9 were run on a Kohler ~91~engine.
~0 This en~ine was ra~d at 4 horsepower and has a 31ngle cyl~nder of ca~t iron. For èvaluatln~ reslstance to mis~lrlng, the en~ine w~ run at 3600 rpm wi~ no added load except ror an lntegral coollng ~en. For the te8t8, ~n extended core plug ::
o~ moderately high ho~t r~e ~AB se~ected. m15 pl~lg ~a8 `~
~ d~ignatlon ~rom A ~o~ AC~65. The he~t range wa~ sult~ble for tu~npike a8 well A8 Rround-town drlving condl~lon~. The :~ ~
extend~d cor~ was c~osen to ln~rea~e the test ~verlty by ~:
expo~ing the plu~ to ~or~ o~ the product~ o~ ~ombustion. qb ~urth~r incr~aDa tho ~erity of the test, t~a el~ctrod@ g~p - 4 _ 1 , . - ~ . , ., . ................. .. ; .- . . -:
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wa~ reduced to 0~015 inche~. The~e severe condltlon~ were cho~en to obtaln the moet lnrormatlve test results in ~he - shorte6t perlod o~ tlme. me re~ults Or these experiment~ :
~ere later conflrmed on ~ull-Ai?~e automoblle en~ines.
Each of the tests was run with A clear ~reshly set plug whlch would ~lve rellable lgnition. Each test waB be~un ~lth ~resh oil and a clean combustion chamber. m e engtne was run ror a perlod o~ 19 hours to provide adequate plug deposlts. men ~or a perlod Or one hour~, the number o~ mls~ires were counted. In some ca8e3, thc englne stalled be~ors a ml~lre count could be made. To detect mlsflre7 the exhau~t llne pressure near th~ exhRust port was monitored with 8 tle~pressure pickup. The exhau9t llne pres~ure depend~d on the lenltlon ~uccess G~ the plug. When a mls~lre occurred, a counter recorded the misrire.
For the exhaust ~ e seal te~t9 the ~ngine ~a~
:Loaded wlth a blower that Rbsorbed 1.5 horsepowsr at 3600 rpm.
That load wa~ 40~ Or the rat~d engine power at the ~peed.
'~he test wa~ run for 2~ hours, uslng a ruel comp~slt~on~ .
?0 contalnlnF. lead a3 described a~o~e.
Example 1 - E~ect Or triethyl citrate on the number o~ mis~ires.
, The m~ng nese ~uel described sbo~e wa~ run ln t~e Xohler cnglnQ. It wa~ determlned that the citr~te c~mpound ~ :
l~pro~ed th~ lgni~ion reliability Or the manganese ~uel.
~5 Inst~nce~ o~ prem~ture stAllinR and mls~re counts ln the 20th hour o~ 13,000 w~re lmproved to no instanc~s o~ stalling and mis~iro counts o~ 2000 or less using triothyl cltrate concentr~lon~ Or battYeen 20 And 1~0 mllll~rams per RRllon~
Egu~lly ra~orabl~ r~ult~ were o~t~ined wlth ~u~l contBinlng bot~ triethyl cltrat~ ~nd t~trabutyl tln.

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`~` !477~) Example 2 - Ef~ect of trlethyl cltrate on plu~ gap deposlts.
The spark plug~ used wi~h the man~ane~e fuel were examined. ~eposlts appeared to ~orm on the plug electrodes as needle~, ex~en~ing ~rom the center electrode towards the ~round electrode. Occa~ionally, such needles brld~ed the ~ap completely, cau~ing the plug to be 3hort~d out. However, ~ith triethyl citrate lncorporated in the ~uel at a level Or 40 milligrams per ~allon, the ~rowth o~ these deposlt~ wa~
substantially ellminated.
E~mple 3 - Effect o~ tetrabutyl tin on valve seal depo~it~.
The leaded mangane~e ~uel described above was run in the Kohler englne. A Y~bstantial deposit accumulated on the exh~u~t valve and se~t which resulted ln a broadened cont~ct in loc~ area~, inter~erlng ~.ith the valve ~eal. ;~
With 20 milligrRms per ~allon of tin as tetra-n-but~l tln, -~ `
the deposits on the val~e closure were very much smal]er and thinner and there was no damage to the valve seal. Simllar favorable results lere obtained USill~ a ~uel contalning both `
tetrs ~utyl tin and trlethyl citrat~
In the same way a~ shown '.ln the examples abo~, trieth~l citrate co-lld be replaced by tripropyl or tri-butyl citrate ~nd the benefits o~ the lnventlon re~llzedO
A~so in the same manner, the tetrabutyl tin could be ~ubstituted by dlbutyl tln dich;oride, dibutyl tin diacetate, dlbutyl tln ~5 Di_~ ethylhexoate or dibutyl tin dllflurate al80 glvlng the deslrable result~ o~ the in~ention in the reduction o~ the dapo~it~.
5hese addltive~ are economically reaslble from the co~t ~tandpoint ~d are not toxic to the extent that th~y '-. ' -~ .

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(1~77~) : ~ould beprecll~ded a8 ga~ollne additlves. Above all~ they ar~ very desirable addltlves ~or gasollne contalni~ m~nganese.
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Claims (4)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A gasoline composition for combustion in a gasoline internal combustion engine comprising gasoline and a gasoline soluble manganese compound as an additive, the improvement comprising including a small but effective amount of a tetra-valent tin compound having at least one alkyl group said compound being soluble in gasoline and acting as a gasoline additive to improve the performance of the gasoline internal combustion engine, said small but effective amount being from about 10 to about 75 milligrams of tin per gallon calculated on the tin contained in the alkyl tin compound.

2. The composition of claim 1 wherein the alkyl tin compound has alkyl groups of about 3 to about 6 carbon atoms.

3. The composition of claim 1 wherein the alkyl tin compound is tetrabutyl tin.

4. The composition of claim 1 wherein the manganese compound is methyl cyclopentadienyl manganese tricarbonyl.